WHAT IS A PLENUM - 1989 Ford Crown Victoria

I doubt a leaking plenum would cause it not to start. Usually a leaking plenum would cause an air leak and make the engine run too fast.
Any trouble codes stored ? Will it start using carb cleaner spray ?

Here are the instructions with a diagram. If you need to enlarge the diagram save it to your picture files and then enlarge it there.

1. Disconnect battery ground cable, then drain cooling system. See: Engine, Cooling and Exhaust\Cooling System\Service and Repair

2. Disconnect heater hoses from heater core. Plug heater hoses and core fittings to prevent coolant spillage.

3. Remove bolt located below windshield wiper motor, attaching left end of plenum to dash panel.

4. Remove nut attaching upper left corner of evaporator or heater case to dash panel.
5. Disconnect vacuum control system supply hose from vacuum source, then push grommet and hose into passenger compartment.

6. Remove all instrument panel retaining screws and pull instrument panel back as far as possible without disconnecting any wire harnesses.
7. Loosen right door sill plate and remove side cowl trim panel.

8. Disengage temperature control cable housing from bracket on top of plenum. Disconnect cable from temperature blend door crank arm.

9. On models w/Automatic Temperature Control (ATC) , remove cross body brace and disconnect wiring harness from temperature blend door actuator and disconnect ATC sensor tube from evaporator case connector.
10. Disconnect vacuum harness at vacuum connector near floor air distribution duct.

11. Disconnect white vacuum hose from outside recirculating air door vacuum motor.
12. Remove two hush panels.

13. Remove one plastic push fastener retaining floor air distribution duct to left end of plenum. Remove left screw and loosen right screw on rear face of plenum. Remove floor air distribution duct.

14. Remove two screws from rear side of floor air distribution duct to plenum. To remove right screw, it may be necessary to remove the two screws attaching lower panel door vacuum motor to mounting bracket.

15. Remove push fastener attaching floor air distribution duct to left end of plenum, then remove floor air distribution duct.
16. Remove two nuts located along lower flange of plenum.
17. Carefully move plenum rearward, so that heater core tubes and plenum case upper stud clear openings in dash panel, then remove plenum from vehicle by rotating upper portion of the plenum forward, down and out from under instrument panel. It may be necessary to carefully pull lower edge of instrument panel rearward while plenum is being removed from behind instrument panel.
18. Remove retaining screws from heater core cover, then the cover from plenum assembly.

19. Remove retaining screw from heater core inlet and outlet tube bracket.

Heater core removal and installation diagram.






20. Pull heater core and seal assembly from plenum assembly.
21. Reverse procedure to install.

Section 12-03: Air Conditioning System 1992 Town Car/Crown Victoria/Grand Marquis Workshop Manual REMOVAL AND INSTALLATION Plenum Removal

1. Disconnect battery ground cable.

1. Disconnect the heater hoses from the heater core tubes. Plug the ends of the heater hoses to prevent coolant loss.

1. Plug heater core tubes securely to prevent coolant leakage from heater core during plenum removal.

1. Remove three nuts located below the windshield wiper motor retaining the LH end of the plenum to the dash panel (Fig. 15).

FIG. 15 Plenum and Air Inlet Duct Removal

1. Remove one nut retaining the upper LH corner of the evaporator case to the dash panel.

1. Remove LH and RH lower instrument panel insulators.

1. Disconnect two vacuum supply hoses from vacuum source. Push grommet and vacuum supply hose into passenger compartment.

1. Remove all instrument panel retaining screws and pull the instrument panel back as far as possible without disconnecting any wire harnesses.

1. Loosen the RH door sill plate and remove the RH side cowl trim panel.

1. On manual systems, disengage the temperature control cable housing from the bracket on top of the plenum. Disconnect the cable from the temperature blend door crank arm. On ATC systems, remove cross body brace and disconnect wiring harness from temperature blend door actuator and disconnect the ATC sensor tube from the evaporator case connector.
   

1. Disconnect the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct.

1. Disconnect the white vacuum hose from the outside-recirculating door vacuum motor.

1. Remove two hush panels.

1. Remove one plastic push fastener retaining the floor air distribution duct to the LH end of the plenum. Remove LH screw and loosen RH screw on the rear face of the plenum (Fig. 14), and remove the floor air distribution duct.

1. Remove two nuts from the two studs along the lower flange of the plenum.

1. Carefully move plenum rearward to allow heater core tubes and the stud at the top of the plenum to clear holes in the dash panel. Remove plenum from vehicle by rotating the top of the plenum forward, down and out from under the instrument panel. Carefully pull lower edge of instrument panel rearward as necessary while rolling the plenum from behind the instrument panel.

Installation

1. Route the vacuum supply hose through the dash panel and seat the grommet in the opening.

1. Position the plenum under the instrument panel with the register duct opening up and the heater core tubes down. Rotate the plenum up behind the instrument panel and position the plenum to the dash panel. Insert the heater core tubes and mounting studs through their respective holes in the dash panel and the evaporator case.

1. Install three nuts on the studs along the lower flange and one on the upper flange of the plenum (Fig. 15).

1. Install three nuts below the windshield wiper motor to attach the LH end of the plenum to the dash panel.

1. Install one nut to retain the upper LH corner of the evaporator case to the dash panel.

1. Position floor air distribution duct on plenum. Install two screws and plastic push fastener.

1. If removed, position panel door vacuum motor to the mounting bracket. Install two retaining screws.

1. Connect the white vacuum hose to the outside-recirculating door vacuum motor.

1. Connect the vacuum jumper harness to the plenum harness at the multiple vacuum connector near the floor air distribution duct. Install floor duct.

1. Connect the ATC sensor tube to the evaporator case connector on ATC equipped vehicles.

1. Install the cross body brace and connect wiring harness to the blend door actuator on ATC equipped vehicles.

1. Connect the temperature control cable housing to the bracket on top of the plenum and connect the temperature control cable to the temperature blend door crank arm. Adjust the temperature cable as outlined under Adjustments.

1. Install the bolt to attach the lower RH end of the instrument panel to the side cowl.

1. Install the RH side cowl trim panel and tighten the RH door sill plate retaining screws.

1. Install glove compartment door and check arms.

1. Connect vacuum supply hose to vacuum supply.

1. Install RH and LH lower instrument panel insulators.

1. Install two hush panels.

1. Unplug the heater core tubes and connect the heater hoses to the heater core tubes.

1. Fill the cooling system with coolant to replace coolant lost during removal of the plenum.

1. Connect the battery ground cable. Check the system for proper operation.

you will have to replace the heater core if you are confirmed the heater valve is cracked.
1. Disconnect the negative battery cable.2. Drain the cooling system and disconnect the heater hoses from the heater core tubes. Plug the hoses and the heater core tubes to prevent coolant leakage.3. Remove the 3 nuts located below the windshield wiper motor attaching the left end of the plenum to the dash panel. Remove the 1 nut retaining the upper left corner of the evaporator case to the dash panel.4. Disconnect the vacuum supply hose(s) from the vacuum source. Push the grommet and vacuum supply hose(s) into the passenger compartment.5. Remove the right and left lower instrument panel insulators.6. On 1990-00 vehicles:
1. Remove the cross body brace and disconnect the wiring harness from the temperature blend door actuator.
2. Disconnect the ATC sensor tube from the evaporator case connector.
7. Disconnect the vacuum jumper harness at the multiple vacuum connector near the floor air distribution duct. Disconnect the white vacuum hose from the outside-recirculating door vacuum motor.8. Remove the 2 hush panels.9. Remove 1 plastic push fastener retaining the floor air distribution duct to the left end of the plenum. Remove the left screw and loosen the right screw on the rear face of the plenum and remove the floor air distribution duct.10. Remove the 2 nuts from the 2 studs along the lower flange of the plenum.11. Carefully move the plenum rearward to allow the heater core tubes and the stud at the top of the plenum to clear the holes in the dash panel. Remove the plenum from the vehicle by rotating the top of the plenum forward, down and out from under the instrument panel. Carefully pull the lower edge of the instrument panel rearward, as necessary, while rolling the plenum from behind the instrument panel.12. Remove the 4 retaining screws from the heater core cover and remove the cover from the plenum assembly. Pull the heater core and seal assembly from the plenum assembly.

the upper intake plenum...you will have to remove the plenum to access the spark plugs...usually you are able to unbolt the plenum only and disconnect the front connectors and/or vacuum lines. and tilt the plenum up and out of the way to access the plugs... take care when doing this you can damage the engine if not careful. make sure you get a new intake plenum gasket...as well as the valve cover gaskets...the rubber rings that seal the spark plug tubes from oil tend to leak causing a misfire. you already have to pull the plenum might as well do the valve cover gasket while you are so far in it.

There are no fasteners inside the plenum, The electrical connection for the injectors is very tight due to a rubber ring gasket the seals the injector assembly to the plenum. Carefully push down on the electrical assmbly while prying up the plenum. You also may have to remove the thermostat and hose. I've done this 3 times on my ladies 96 Yukon.

My 2002 Land Rover Freelander V6 thermostat crapped out as well and I decided to replace it myself.

The plenum is deceptive, but after 3 hours of looking and trying I finally got it off. Of course there are many hoses and electrical connections that need to be removed, but that's the easy part because you can see them all. The bolts that hold on the plenum are what your worried about and I will now tell you where they are. Read this and you should take about 30min to remove the plenum.

There are a total of 6 bolts to be removed that secure the intake plenum to the intake manifolds.

First remove the 4, 10mm large and obvious bolts at the top of the plenum. Now here is the tricky part, there are 2 bolts that are at the back of the plenum near the fire wall. As you are looking at the intake plenum from the front of the car, they are on the back side of the plenum near the fire wall on the passenger and driver side of the intake plenum.

Both bolts your looking for are 8mm bolts. If you remove a 10mm bolt, your removing the bolts that secure the rear spark plug coils.

The driver side rear intake plenum 8mm bolt is secured to the plenum itself. Fell with your hand about the back of the plenum on the right side for a lone bolt that is in the plenum with a metal tab that goes down to the back of the rear cylinder head. Remove the bolt that is attached to the intake plenum, not on the rear cylinder head

The passenger side one is a bit different. Feel on the back of the intake plenum about the passenger side for a metal support tab that comes down from the intake plenum and secures to the rear cylinder head. Where the support tab attaches to the head is a 8mm bolt that you remove.

Now here come the leap of faith. If you have the 4, 10mm obvious bolts removed and the 2, 8mm from the rear of the plenum removed, and if you can rock the plenum up and down about 2-3 inches,but it still feels like its attached to the intake manifolds in the middle of the engine, then you have removed all the bolts that secure the intake plenum to the engine. This is good.

The intake plenum is now being held on by the rear intake manifold by 3 O-ring gaskets. Push onto the back of the intake plenum near the firewall to expose a gap at the front of the intake plenum at the front intake manifold. Put 2-3 long flat screwdrivers into the gap or a small pry bar, and ever so gently but forcefully, apply prying force as to not damage the mating surface of the aluminum intake manifold, until the intake plenum pops off. It will just POP off.

Now that the intake plenum is popped off, take careful note of all the electrical plugs and hoses as to where they attach. You will not need any tools to disconnect the electrical plugs or hoses. To remove the hoses, push down the red ring with you fingers that the hose goes into and pull on the hose, it should come out very easily. The electrical connectors, push on the metal clip down and pull the connector loose. The electrical connectors only plug into their own plug, so you cant mess them up.

Tools you will need to replace the thermostat;

1. 8mm combo wrench. Make sure its not too long, shorter is better.
2. 10mm socket, shallow. 10mm combo wrench
3. 2-3 flat screwdrivers, for prying off the intake plenum
4. Ratchet wrench
5. 1 foot long worth of socket extensions. 2 6inch extensions will work as well
6. Universal socket joint
7. Angled needle nose pliers make it easier for hose clap removal, but straight needle nose pliers will work
8. Diagonal cutters to cut securing zip ties for the wiring harness

Take you time, once the plenum is off it goes pretty smooth after that. We removed just the forward intake manifold and that was more than enough clearance to remove the thermostat. You do not need to remove the fuel rail or spark plug coils from the manifold but you will need to disconnect the electrical connections to move the intake manifold out of the way.


Take pictures, there's a lot of hoses that go all over the place. The electrical connectors are only long enough to go where their supposed to go.

Then take that UK piece of **** to the dealer and trade it in for anything made in the USA or Japan. Changing a thermostat in any of those will only take 10 min and require 1 tool.

Repair provided by KPCYCLES.com of Honolulu, HI

your blower resistor is bad

you have to remove the plenum case behind the dash. I will provide 94 gr marquis. don't have 84.



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Section 12-03A: Air Conditioning System—Manual A/C-Heater 1994 Crown Victoria/Grand Marquis. Workshop Manual
REMOVAL AND INSTALLATION Heater Core Removal

1. Remove the heater air plenum chamber assembly as outlined.
2. Heater Air Plenum Chamber Removal
   
   1. Disconnect battery ground cable .
   1. Disconnect the heater water hoses from the heater core tubes. Plug the ends of the heater water hoses to prevent coolant loss.
   1. Plug heater core tubes securely to prevent coolant leakage from heater core during heater air plenum chamber removal.
   1. Remove three nuts located below the windshield wiper motor (17508) retaining the LH end of the heater air plenum chamber to the dash panel .
   1. Remove one nut retaining the upper LH corner of the A/C evaporator core housing to the dash panel .
   1. Remove LH and RH lower instrument panel insulators.
   1. Disconnect two vacuum supply hoses from vacuum source. Push grommet and vacuum supply hose into passenger compartment.
   1. Remove all instrument panel retaining screws and pull the instrument panel back as far as possible without disconnecting any wire harnesses.
   1. Loosen the RH door sill plate and remove the RH side cowl trim panel.
   1. Remove cross body brace and disconnect wiring harness from A/C electronic door actuator motor (19E616) and disconnect the sensor tube from the evaporator case connector.
   1. Disconnect the vacuum jumper harness at the multiple vacuum connector near the heater outlet floor duct.
   1. Disconnect the white vacuum hose from the heater and A/C air inlet duct door vacuum control motor.
   1. Remove two hush panels.
   1. Remove one plastic push fastener retaining the heater outlet floor duct to the LH end of the heater air plenum chamber . Remove LH screw and loosen RH screw on the rear face of the heater air plenum chamber and remove the heater outlet floor duct .
   1. Remove two nuts from the two studs along the lower flange of the heater air plenum chamber .
   1. Carefully move heater air plenum chamber rearward to allow heater core tubes and the stud at the top of the heater air plenum chamber to clear holes in the dash panel. Remove heater air plenum chamber from vehicle by rotating the top of the heater air plenum chamber forward, down and out from under the instrument panel . Carefully pull lower edge of instrument panel rearward as necessary while rolling the heater air plenum chamber from behind the instrument panel .

1. Remove the four retaining screws from the heater core cover (18B300) and remove the heater core cover from the heater air plenum chamber assembly.
   
   Heater Core Removal
   
   
   
   
   
   Item Part Number Description 1 390092-S2 Screw (2 Req'd) 2 18658 Heater Core Case Seal 3 18476 Heater Core 4 18570 Heater Dash Gasket 5 18471 Heater Air Plenum Chamber 6 18B300 Heater Core Cover

1. Pull the heater core assembly from the heater air plenum chamber assembly.

Installation

1. Carefully install heater air plenum chamber assembly into the heater air plenum chamber assembly. Visually check to ensure that core seal is properly positioned.

1. Position the heater core cover and install the four retaining screws.

1. Install the heater air plenum chamber assembly as outlined.

The best way to remove the rear valve cover is to remove the intake plenum. There is really no other way to do it. It is not a hard job, removing the intake plenum, but, trying to tackle the rear cover without taking off the plenum is almost impossible. If he does remove the plenum, make sure he replaces the plenum gasket. Hope this helps.
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